Functional blocks for fastening circuit-carrying cards to a fixed, and often common, support have been known for a long time. Thus, for example, the Applicants' U.S. Pat. No. 3,833,839 describes a terminal box for fixing a printed circuit card on a section bar and for electrically connecting the card to the conductors required for its use via various terminals and tongues.
Such functional blocks are well adapted to mounting component-carrying cards of predetermined size and not exceeding some limited bulk; however, they can be adapted over only a small range of sizes which leads to a multiplicity of models of various sizes, with all the drawbacks that can entail.
Research is thus currently being performed to provide functional blocks made up from a small number of component parts which can readily be combined so as to make assemblies of different sizes depending on user requirements.
This leads to a search for component parts which are simple in shape, which are easy to use, which are cheap, and which should, if possible, be compact in order to facilitate storage.
Preferred implementations of the present invention satisfy the above requirements.